This invention refers to a ball joint intended for different applications, where it is required the connection between two distinct parts, but with relative movements controlled between both parts, particularly a car suspension.
Ball joints are generally composed of a pin with a spherical end, which is housed in a bearing located inside a housing. Part of the pin and the external part of the housing is available for mounting and fixing in their respective counterparts, allowing then the rotation and oscillation between them, as shown in the German Patent DE 1 575 684. It is known the method of encasing the sphere of the pin in the bearing, that has an internal profile also spherical and the surface of which will serve as a sliding track for the pin. The bearing, by its turn, will be mounted in the housing through its opening, their profiles being coincident, guaranteeing the mounting condition. On the bearing will be mounted, still through the opening of the housing, a ring whose internal diameter will allow the passing of the pin""s body, but not of its spherical part, what would lead to the dismounting of the assembly. The ring is typically pressed on the bearing, and that consequently will press the sphere of the pin during the closing operation of the assembly. This hinders the axial and radial movements between the components, but without hindering in this way the rotation and oscillation movements of the pin on the internal surface of the bearing.
In this special type of construction, the ring still supports the sealing parts, made of elastic material, and may be embodied inside them, whose technical standard is duly characterized by U.S. Pat. No. 5,066,159, or with its perimeter partially adhered to the sealing parts, characterized by the patent PI 9405521-2-A.
However, he sealing parts commonly used in ball joints, when exposed, are prone to ruptures, perforations and tearing by external elements, not only during the transport and the mounting but also during the use in its application, thereby subjecting the internal region to the penetration of impurities and contaminants, leading to the reduction of the ball joint life.
In the case of the ring being entirely covered by a layer of the sealing part material, as mentioned in previously identified U.S. Pat. No. 5,066,159, the existence of this layer between the bearing and the ring and between the closing rim and the ring will allow a certain undesired axial movement of the pieces, due to the elastic characteristics of this material. Further, it is known that in this model the facility in the damaging of the sealing parts, in the case of extreme oscillatory movement of the pin.
In the case where the ring has a perimeter partially adhered to the sealing parts, as mentioned in previously identified patent PI 9405221-2A, the sealing part is vulcanized in the internal lateral wall of the ring throughout its internal diameter and in an adjacent area of the upper part thereof. In principle, this construction impairs penetration of impurities and contaminants between the pin and the ring. But, due to the small dimensions of the closing rim on the ring, this construction does not efficiently accommodate a sealing layer and also an area of direct contact between the closing rim and the ring simultaneously. Accordingly, penetration of impurities and contaminants is not actually impaired, and may still allow an undesirable axial movement of the pieces, as the control of this movement is not effective. Besides, this construction has sealing efficiency only when the joint is constructed by utilizing a single bearing with a tab projecting upon the upper part of the housing. The sealing is carried on by the pressing of the tab between the sealing ring and the upper part of the housing.
The objective of the invention is to present a technical and economically viable solution for ball joints exposed to impurities and contaminants with need of sealing during its application, without restriction as to the type of bearing to be utilized. This may be accomplished through the use of a retaining ring whose perimeter is connected to two distinct sealing pieces: an external sealing, connected by vulcanization along the external diameter of the retaining ring, extending itself until the internal diameter of the housing to guarantee sealing between the housing and the retaining ring; and an internal sealing, connected also by vulcanization along the internal diameter, promoting a flexible strut for the pin in case of extreme moving, and part of the upper surface of the retaining ring, extending itself until the pin, with a profiled favorable to the flexibility required to the sealing part during the different situations of inclination of the pin, guaranteeing in all situations the sealing between the pin and the retaining ring. The mounting facility is maintained and the axial movement between the parts is thereupon perfectly controllable, without damaging any part of the assembly.